The problem you are encountering is probably an integration one, whereas integration with VS LightSwitch is not supported yet.

We will investigate it and inform you about the results, but please notice that dotConnect for Oracle is not supposed to be used with the LightSwitch VS edition, nor do we guarantee they are compatible.

The new build of dotConnect for Oracle 6.10.96 with improved LightSwitch performance is available.
It can be downloaded from here (trial version) or from Registered Users' Area (for users with valid subscription only).
For more information, please refer to this announcement.